The e-mail address is encrypted since CS v9.1.1 in a very secure way. But nonetheless prior to v9.1.1 your e-mail address was obscured but feasible to reverse it.

However regarding the other data (quiz question, quiz answers, etc) you shouldn't put anything private such as passwords, phone numbers, credit card numbers, etc in them. This is because this information is in plain text in a XML-like file that your web browser retrieves when viewing your video. It would not be difficult for somebody to bring up developer tools within the web browser and see the contents of this file.

If you are sharing your video publicly such as on Screencast.com or on the Internet somewhere it could be discovered and this other data could be read. But if your video is only accessible from an internal network it is as secure as you provided it.